You have no clue. How do you extract wealth without development in the first place?
You have to start with transportation networks, farms, and mines. Only later can you do further development.
Dodo, you're all over the place. You want to enter another person's land, get paid a king's ransom for resource extraction and then flee. When you don't get your way you start moaning about 'Africans'. Let me school you: Africa is a big place, over three times the size of China and we know China is a large country. Africa has about 54 countries, each of those countries are made up of distinct ethnic nations with different cultures, politics, and levels of economic development. In case you haven't processed all of this, it means countries are different. But I know your type, you're really just a westerner so you've adopted their western racist outlook that's difficult to shake off that's why you're doubling down. So let me ask again, what country did your contractor friend work in? Congo? Angola? Because those are distinct and sovereign countries, what they do has nothing to do with others. Whatever happens in Cambodia or Thailand has nothing to do with China, or is in right to lump all of Asia into one based on the behavior of one? What does a foreign national being murdered in South Africa have to do with Botswana for example?
Just so you know the Chinese are all over the continent helping to build infrastructure, many of them living and working there. For the most part there are no problems but operations of that scale you'll hear some negative stories that from time to time, that's normal and to be expected. Nothing is ever going to be perfect.